One of the requirements for flying in a spaceship used to be near-perfect vision. When NASA relaxed its vision standards (to 20/200 or better uncorrected, correctable to 20/20 each eye for a mission specialist) they in turn created a new requirement–for near-perfect astronaut eyeglasses.

TruFocals (made by Zoom Focus Eyewear, LLC) might improve current astronaut spectacles by allowing space-travelers to focus mid-float on both near and far objects, whether they’re dealing with experiments or cooling loop warning indicators. As Scientific Americanreports, the glasses are currently undergoing NASA evaluation for space readiness–tests that include burning. The lenses will correct the condition known as presbyopia, in which aging people’s eyes lose focusing ability, making it difficult to see near objects. That’s the condition that causes people with good eyes to pick up reading glasses, and those with glasses to turn to bifocals.

These space glasses aren’t much like your grandma’s bifocals. TruFocals have two lenses for each eye: the outer lens uses the person’s usual prescription and the inner lens (closer to the the eye) is flexible and controllable by a slider on the eyeglasses’ bridge. With a little slide the shape of the inner lens changes, allowing the wearer to adjust their focus. That could be handy in an environment like the International Space Station, where floating astronauts may be trying to focus on things from odd angles.

The round shape is a necessity for the glasses to work best, Stephen Kurtin the glasses’ inventor toldScientific American, not a fashion decision:

“Some people say they’re cool, and some say they’re butt ugly.”

NASA may approve the glasses in time for the next space mission, though, as shown in the target-practice video below, the lenses are already available for planet dwelling four-eyes.